1. Field of the Invention
The present invention relates to a surface wave excitation plasma processing device for performing various treatments by using surface wave excitation plasma.
2. Description of Related Art
As for plasma processing devices capable of generating plasma with high density and over a large area, devices using surface wave excitation plasma are well known. In such devices, it is well known to those skilled in the art that, the microwave waveguide is branched and disposed on a dielectric plate in parallel, such that microwaves guided from a microwave generating part propagate through each microwave waveguide via a plurality of branches, and microwave power is acquired from the dielectric plate in a wider range, thereby realizing a device capable of uniform generation of plasma over a large area (with reference to, for example, Patent Document 1).
[Patent Document 1] Japanese Patent Publication No. 2005-33100 (Page 2, FIGS. 1, 4).
By using the device described in the Patent Document 1, the microwave power can be distributed on a plurality of microwave waveguides with branches so as to generate plasma in a large area. However, in the device described in the Patent Document 1, due to the slight changes of the plasma as a load, the combining status between the microwave power and the plasma of each waveguide is also changed sometimes, such that the distribution ratio of the power input into each waveguide is changed, thus resulting in a failure of obtaining uniform plasma.